The concept of dip-molding coverings or hollow shells for tool handles to provide a soft hand grip is well known in the art. An example of dip-molding using a mandrel is shown in U.S. Pat. No. 4,695,241 wherein an internal passage is provided so that a hollow part can be dip-molded. Still another example of dip-molding to form an electrical socket is shown in U.S. Pat. No. 5,350,318 wherein a wire lead is wrapped around a projection to form a socket and the wire lead and the projection are coated with a layer of plastisol.
In the formation of twist-on wire connectors one places a hard or rigid shell around a twist-on wire connector. To form a twist-on wire connector one forms a cavity and then injection molds plastic into the cavity to form a hollow shell for supporting a wire coil therein. A method of making twist-on wire connector is shown in King U.S. Pat. No. Re37340 and King U.S. Pat. No. 5,151,239 which shows the formation of an injection molded shell around the exterior of the twist-on wire connector by first forming a mold cavity and placing the twist-on wire connector in the cavity and then injecting a moldable plastic into the mold cavity to form an injection molded shell around the twist-on wire connector.
An example of a twist-on wire connector with a hard shell surrounding the spiral wire coil and a soft sleeve engaging a portion of the shell is shown in the U.S. Patent Application Publication 2002/0050387. The Publication shows six different sleeves which are separately formed and then placed around a portion of the exterior surface of a twist-on wire connector for the purpose of forming a cushion grip on the twist-on wire connector. In another embodiment U.S. Patent Application Publication 2002/0050387 a portion of the twist-on wire connector is over molded with a softer material to provide a cushion grip on a portion of the twist-on wire connector. While these inventions are for the purposes of providing a soft grip they do not address the problem of making the twist-on wire connector with enhanced impact resistance.
In contrast to the above art, the present invention provides a method for forming a twist-on wire connector with enhanced impact resistance. That is, to prevent the wires from coming loose from the twist-on wire connectors the inclusion of a dip-molded shock absorber covering on the twist-on wire connector provides enhanced impact resistance that inhibits wires from coming loose in the twist-on wire connector as well as cracking to protect from dielectric failure. A twist-on wire connector can be formed without the aid of a mold through a dip-molding process. In another method a twist-on wire connector is dipped into a bath of a dip-molding compound that solidifies in-situ. Dip-molding compounds include vinyl compound such as plastisol. The dip-moldable materials which can be in liquid or gel form surrounds the exterior surfaces of the twist-on wire connector. As the dip-molding compound cools around the connector it provides an in-situ formation of an impact resistance covering or shell on the outside of the exterior surface of twist-on wire connector to provide a soft-to-the-touch dip-molded shell that has enhanced impact resistance.
In another method a twist on wire connector spiral coil is placed on the end of a mandrel and dipped into a mold of liquid plastic. The liquid plastic is allowed to solidify around the mandrel to provide for an in-situ formation of an impact resistance shell around the mandrel. The mandrel is then removed leaving the spiral coil in the shell.
In still another method the mandrel is provided with a shape of a spiral coil and is dipped in a vat of liquid plastic to form a covering around the mandrel. The mandrel is then removed and the covering is allowed to solidify for in-situ formation of a shell. In the next step a spiral coil is inserted into the dip-molded shell to form a twist-on wire connector with an impact resistance shell.
In still another method the mandrel with a set of fins is dipped into the vat of dip-moldable material while the dip-moldable material is allowed to flow inward to form an integral cover on the housing with the integral cover having flexible portions to allow removal of the mandrel after the solidification of the dip-moldable material about the mandrel.